a study of aliphatic hydrocarbons levels of … · (31.421 µg/l). the maximum concentration at...

________________________________________

*Author for correspondence; E-mail: [email protected]

Int. J. Chem. Sci.: 11(2), 2013, 833-849ISSN 0972-768X

www.sadgurupublications.com

A STUDY OF ALIPHATIC HYDROCARBONS LEVELS OF SOME WATERS AND SEDIMENTS AT AL-GABAL

AL-AKHDER COAST REGIONS

HAMAD M. I. HASAN* and ABDALRAZK S. A. MOHAMAD

Chemistry Department, Faculty of Science, Omarel Mukthar University, LIBYA

ABSTRACT

Determinate the concentration of individual aliphatic hydrocarbons in water and sediment samples collected from different locations which distributed on Al-Gabal Al-Akhdar coast. The total aliphatic hydrocarbons TALHs in the water samples were fluctuated between (8.680-88.885 μg/L). While in the sediment were ranged between (26.313-1069.183 ng/g). High levels of carbonate were recorded in all sediment samples. The total carbon contents were ranged between (1.15-2.6%). The special TALHs compound ratios Pr/Ph the detection of these two components is often used as good indicators of petroleum contamination while a CPI approaching unity indicates great inputs from aquatic organisms the ratio of (n-C17/pr) and (n-C18/ph) indicating contributions from biogenic origins and contribution from petrogenic sources.

Key words: Aliphatic hydracarbon, Al-Gabal Al-Akhder coast.

INTRODUCTION

Mediterranean sea appears to suffer from high anthropogenic pressure due to inputs from; industrial, sewage effluents, storm water drains, shipping activities, spillage, rivers, atmospheric-fallout, coastal activities and natural oil seeps1. The annual inputs of petroleum hydrocarbons are about 750 × 103 tons, among which the land-based industrial inputs amount are about 221 × 103 tons per year2. Thus, the distribution of hydrocarbons in the environment can vary greatly from one area to another. Clark3 stated that polycyclic aromatic hydrocarbons (PAHs) and aliphatic contamination in sediments originate mainly from the following sources:

(a) accidental spills; (b) partial combustion of fuels (pyrolytic combustion of fossil fuels such as in vehicles, heating and power plants, industrial processes and/or open burning);

H. M. I. Hasan and A. S. A. Mohamad: A Study of Aliphatic…. 834

(c) forest and grass fires (d) biosynthesis by marine or terrigenous organisms (land plants, animals, bacteria, macroalgae and microalgae, bacterial and chemical degradation of naturally occurring lipids produced hydrocarbons such as phytanes, hopenes and sterenes); (e) early digenetic transformation of non hydrocarbon natural products to hydrocarbons.

Hydrocarbon composition can be significantly changed due to selective dissolution, chemical reactions, evaporation, photo-oxidation and biodegradation. Simple aromatics and short chain alkanes are rapidly lost, but higher molecules such as hopanes and steranes are little affected and can be particularly useful in source investigations4.

PAHs (poly aromatic hydrocarbons) are one of the more significant classes of organic chemicals that in the recent years have given rise to a growing concern regarding harmful effects to man and other living organisms.

EXPERIMENTAL

Materials and methods

Sampling

Surface water samples were collected using a Nisken bottle from 8 locations, distributed along Al-Gabal Al-Akhder (LIBYA) during summer 2011 (Fig. 1). A total of 4 surface sediment were collected from the sites. The locations were selected, taking into consideration the expected polluted area due to industrial and human activities. Sediments were collected utilizing a stainless-steel grad from which the top 3 cm were scooped into pre-cleaned wide-mouth glass bottles, frozen, and transported to the laboratory.

Water samples were extracted on board, stored at -4ºC, and transported on the laboratory for aliphatic and PAHs analysis using well-established techniques5. Seawater samples were extracted three times with 60 mL of dichloromethane in a separating funnel. Sample extracts were combined and concentrated by rotary evaporation to 5 mL. Finally, samples were concentrated under a gentle stream of pure nitrogen to a final volume of 1 mL.

Sediment analysis

Organic carbon was determined using acid/dichromate titration method as reported6. About 0.2-0.5 g was dried and placed in a 500 mL Erlenmeyer flask. Exactly 10 mL of 1 N K2Cr2O7 solution was added to the sediment and the two were mixed by swirling the flask. 20 mL of concentration H2SO4 were added by burette and mixed by gentle rotation of the flask for about one minute. After 30 min, the solution was diluted to 200 mL volume with

Int. J. Chem. Sci.: 11(2), 2013 835

distilled water, and 10 mL (85% H3PO4). 0.2 g NaF and 15 drops of diphenylamine indicator were added to the sample flask. The solution was back titrated with 0.5 N ferrous ammonium sulfate solution. The result of the analysis were calculated by the following equation:

% Organic carbon = 10 (1-T/S) [1.0 N (0.003) (100/W)]

Where; T = Sample titration, mL ferrous solution, S = Standardization blank titration, mL ferrous solution, 0.003 = meq. Weight of carbon, 1.0 N = Normality of K2Cr2O7 in mL and W = Weight of sediment sample in grams.

About 3-4 g of each of sediment sample was taken and weighed in an aluminum dish. Samples were oven-dried at 105oC to a content for each sample. Before chemical treatment, individual samples were removed from the refrigerator and allowed to thaw at room temperature for about 5 h. Each sample was then thoroughly mixed, and 30 g of the sediment was mixed with 90 g of anhydrous sodium sulphate. Duplicates were taken from each sediment sample. The sediment sample was then extracted in a Soxhlet extractor with 250 mL of hexane for 8 h and then re-extracted for 8 h into 250 mL of dichloromethane. The extracts were then concentrated to a few milliliters in a rotary evaporator al low temperature (35ºC), followed by concentration with a nitrogen gas stream down to a volume 1 mL.

Clean-up and fractionation were performed by passing the extract (water or sediment or biota samples) through a silica/alumina column. Silica column was prepared by slurry packing 20 mL (10 g) of silica, followed by 10 mL (10 g) of alumina and finally 1 g of anhydrous sodium sulfate. Elution was performed using 40 mL of hexane (F1: aliphatic fractions), then 40 mL of 90/10: hexane/dichloromethane (F2: aromatic fractions), followed by 20 mL of 50/50 : hexane/dichloromethane (F3: polyaromatic fractions), both of F2 and F3 fractions were combined to give PAHs. Finally, eluted samples were concentrated under a gentle stream of purified nitrogen to about 0.2 mL, prior to injection into GC/FID for PAHs analysis.

All samples were analyzed by a Hewlett Packard 5890 series II GC gas chromatograph equipped with a flame ionization detector (FID). The instrument was operated in split less mode with the injection port maintained at 290oC and the detector maintained at 300oC. Samples were analyzed on a fused silica capillary column HP-1, with 100% dimethyl polysiloxane (30 m length, 0.32 mm i.d., 0.17, m film thickness). The oven temperature was programmed from 60 to 290oC, changing at a rate of 3 C min-1 and maintained at 290 C for 25 min. The carrier gas was nitrogen flowing at 1.2 mL min-1.


A stock solution containing the following PAHs was used for quantification: naphthalene, acenaphthylene, accnaphthene, fluorene, phenanthrene, anthracene, fluoranthene, benzo (a) anthracene, chrysene, benzo (b) fluoranthene, benzo (k) fluoranthene, pyrene, benzo (a) pyrene, dibenzo (a,h) anthracene, benzo (ghi) perylene and indeno (1,2,3-cd) pyrene by dilution to create a series of calibration standards of PAHs at 0.1, 0.25, 0.5, 0.75, 1.0, 2.0, 5.0 and 10,….g mL-1. The detection limit was approximately 0.01, …g mL-1 for each PAH. For analytical reliability and recovery efficiency of the results, six analysis were conducted on PAH reference materials, HS-5 and 2974 (provided by EIMP-IAEA). The laboratory results showed a recovery efficiency ranging from 92 to 111% with a coefficient of variation (CV) of 8-14% for all studied pollutants (16 PAHs fractions). All solvents were of pesticide grade purchased from Merck, and appropriate blanks (1000-fold concentrates; two for each batch of analysis for both of water, sediment and samples) were analyzed.

Fig. 1: The stations of study

RESULTS AND DISCUSSION

Aliphatic hydrocarbons (ALIP)

Water sample

The concentrations of total aliphatic hydrocarbons (TALIP) and n-alkanes from C10-C40 as well as the isoprenoid hydrocarbon individual concentrations are shown in (Table 1). TALIP in the water samples varied from 8.680 to 88.885 µg/L with an average of (31.421 µg/L). The maximum concentration at station (1) and the low concentrations were recorded at station (8).

Table 1 give total concentration of n-alkanes ranging from C10-C40. The concentration

Int. J. Chem. Sci.: 11(2), 2013 837

below their limits of detection were given a value of zero for the calculation. In the present study the total n-alkanes varied from 7.952 to 81.37 µg/L. The average of total n-alkanes concentration was 28.40 µg/L. Higher concentration occurred at sites (EL-hamama) with value 81.37 µg/L Site (1).

Figs. 2-6 show the individual concentrations (µg/L) of aliphatic hydrocarbons in water samples and the Fig. 7 shows the total aliphatic hydrocarbons in water samples. Table 1 shows that Station 1 was the most contaminated stations with 88.885 µg/L. This clearly reflects flourishing of zooplankton as biogenic inputs of aliphatic hydrocarbons.

Table 1: The concentrations (µg/L) of aliphatic hydrocarbons of water samples

Concentration µg/L Station Name 1 2 3 4 5 6 7 8

Average

C12 0.441 0.310 ― 0.022 ― 0.334 0.279 ― 0.277

C13 0.058 0.203 ― 0.226 ― ― ― 0.083 0.142

C14 0.259 0.282 0.039 0.509 0.016 0.172 0.148 0.319 0.218

C15 0.962 0.140 0.243 0.087 0.030 0.014 ― ― 0.246

C16 0.053 0.132 0.026 0.316 0.123 0.889 1.040 0.951 0.441

C17 12.328 13.487 1.254 11.628 1.903 0.826 1.168 6.085

Pristane 1.067 2.702 1.423 1.604 0.880 0.839 0.657 0.655 1.228

C18 3.330 0.822 0.781 1.016 0.468 0.951 0.228 0.045 0.955

Phytane 6.448 1.691 1.038 2.540 0.855 1.232 0.466 0.073 1.793

C19 17.912 5.118 2.101 6.108 1.970 2.731 1.238 0.325 4.688

C20 13.528 3.529 1.778 5.042 1.609 1.992 0.950 0.632 3.632

C21 9.830 1.195 4.059 4.474 3.156 3.957 0.468 2.564 3.713

C22 6.365 7.524 1.854 3.285 0.976 0.444 0.673 1.392 2.814

C23 6.657 4.716 0.913 0.169 0.126 0.173 0.931 0.223 1.739

C24 6.187 4.818 0.761 2.831 0.148 0.052 1.155 0.229 2.023

C40 3.458 3.434 4.023 1.452 1.962 1.017 2.859 1.188 2.424

∑ALIP 88.885 50.103 20.291 41.308 14.223 15.623 12.259 8.680 31.421

∑n-alkanes 81.37 45.71 17.83 37.164 12.488 13.522 11.136 7.952 28.40 Were: 1 and 2 El-hamama sites, 3 and 4 El-Haniea sites, 5 and 6 Susa sites, 7 and 8 Ras ahilal sites


Aliphatic hydrocarbons

Sample

1Aliphatic hydrocarbons

Indi

v idu

a l c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phyta

neC18

Pristan

eC17

C16C15

C14C13

C12

18161412

1086420

Sample


Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13C12

14

12

10

8

6

4

2

0


Fig. 2: The individual concentrations (µg/L) of aliphatic hydrocarbons for water samples (1 and 2)

Sample 3Aliphatic hydrocarbons

Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

4.03.53.02.52.01.51.00.50.0


Sample


Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13C12

12

10

8

6

4

2

0



Int. J. Chem. Sci.: 11(2), 2013 839

Sample

5Aliphatic hydrocarbonsIn

divi

d ual

con

c. (

g/L

)μ

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

3.0

2.5

2.0

1.5

1.0

0.5

0.0


Sample


Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13C12

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0



Sample


Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phyta

neC18

Pristan

eC17

C16C15

C14C13

C12

3.0

2.5

2.0

1.5

1.0

0.5

0.0


Sample


Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phyta

neC18

Pristan

eC17

C16C15

C14C13

2.5

2.0

1.5

1.0

0.5

0.0




Sample 8

Sample 7

Sample 6

Sample 4

Sample 4

Sample 3

Sample 2

Sample 1


Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13C12

1816141210

86420

ALIP (Sample 1) ALIP (Sample 2) ALIP (Sample 3) ALIP (Sample 4) ALIP (Sample 5) ALIP (Sample 6) ALIP (Sample 7) ALIP (Sample 8)

Fig. 6: The individual concentrations (µg/L) of aliphatic hydrocarbons for water

samples from (1 to 8)

1 2 3 4 5 6 7 80

20

40

60

80

Station

TALIP (μg/L)

TA

LIP

(μg/

L)

Station

TA

LIP

(μg/

L)

0 1 2 3 4 5 6 7 8 90

20

40

60

80

100 TALIP (μg/L)

Fig. 7: The TALIP concentrations (µg/L) for water samples and stations

It was reported that, the isoprenoid hydrocarbons, pristane (Pr) (2,6.10,14-telramethylpentadecane) and phytane (Ph) (2,6,10,14-tetramethylhexadecane), are products of geological alteration of phytol and other isoprenoidyl natural products, and are not primary constituents of most terrestrial biota7,8. Pr and Ph are prresented in most petroleum oils in a ratio of Pr/Ph < 1, so the detection of these two components is often used as good

Int. J. Chem. Sci.: 11(2), 2013 841

indicators of petroleum contamination. However, a high concentration of pr alone can be derived from zooplankton9. In uncontaminated waters, the ratio Pr/Ph is > 1, typically between 3 and 510. Table 2 showed that pr/ph was < 1 for stations (1,4,5,6) indicating mainly petrogenic hydrocarbons inputs. High pr/ph ratio was >1 for stations (2, 3, 7, 8) reflecting biogenic origin.

Tables 2, indicating mainly biogenic origins of the AL-gable AL-akder coast. The predominance of even carbon numbered as C16 and C18. Could be explained as a consequence of microbial activity11. The odd/even carbon ratio, or Carbon Predominance Index (CPI) > 1, reflects that the major source of n-alkanes is terrestrial, mostly aquatic plants, while a CPI approaching unity indicates great inputs from aquatic organisms12. The present study showed that 24% of stations recorded CPI < 1 which may reflect microbial activity.

However, about 76% of stations recorded have CPI > 1 reflecting terrestrial source from aquatic organisms result from flourishing of zooplankton as biogenic inputs of aliphatic hydrocarbons (Table 2). Also, it is noted that the ratio of (n-C17/pr) in most water samples was > 1 indicating contributions from biogenic origins except sites (3, 6, 8) was < 1 indicating hydrocarbons contribution from petrogenic sources (Tables 2). The ratio of (n-C18/ph) in all stations was < 1 indicating hydrocarbons contribution from petrogenic sources (Table 2).

Table 2: Total aliphatic hydrocarbons concentrations (µg/L) with diagnostic ratios of water samples

Ratio station

TALIP (µg/L)

Total n-alkanes (µg/L) (C17/pr) (C18/ph) CPI Pr/Ph

1 88.885 81.37 11.5538 0.5164 1.42 0.1654

2 50.103 45.71 4.4914 0.4861 1.19 1.5978

3 20.291 17.83 0.8812 0.7524 0.92 1.3709

4 41.308 37.164 7.2493 0.4 1.56 0.6314

5 14.223 12.488 2.1625 0.5473 1.35 0.9943

6 15.623 13.522 0.9845 0.7719 1.31 0.6810

7 12.259 11.136 1.7777 0.4892 0.51 1.4098

8 8.660 7.952 Zero 0.6143 0.67 8.9726


In general, that meaning indicate that hydrocarbons origin mixed from petrogenic sources and biogenic origins in sites (1, 2, 4, 5, 7) (Table 2).

Sediment samples

Total organic carbon (TOC %)

The compositions and structures of the organic carbon in the sediment are varying due to its origin and geological history in the marine and aquatic environment. Phytoplankton and zooplankton are the most abundant source of the organic material in the sediments13. The organic Carbon content of the sediment is a result of contribution of teragenous materials and the decomposition of plants and animals by the action of bacteria14.

The values of organic Carbon, (Table 3) and (Fig. 8), were 1.6% 1.42, 2.6% and 1.15 at El-Hamama, El- Haniea, Susa and Ras alhilal, respectively.

1 2 3 40.0

0.5

1.0

1.5

2.0

2.5

Station

TO

C %

TOC %

Station

TO

C %

TOC %

1.0 1.5 2.0 2.5 3.0 3.5 4.01.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

Fig. 8: The concentrations of (TOC %) of the studied sediment

The high TOC% content at Susa area is mainly attributed to discharging of sewage and domestic wastes from out lets and/or susa harbour. Accumulation of organic carbon in sediments is affected by the size of the basin, the wide of the continental platform, the lootom relief, and other morphological features. Physical (temperature, light, oxygen, etc.) and biological characteristics (competition among species, reproduction) are critical factors in the establishment and maintenance of the species inhabiting a sediment.

Int. J. Chem. Sci.: 11(2), 2013 843

The quantitative distribution of organic matter content in the sediment depends principally on some factors:

• The allochthonous organic load entering into the waters with sewage and industrial wastes.

• The autochthonous organic production of the sediments.

• The decomposition of organic matter.

• Particle composition of the sediments.

Carbonate: (CO3-2 %)

The total carbonate content is certainly the most important environmental factor and one of the equilibrium systems in the marine environment. It plays an important role in constructing the shells in all species. CaCO3 precipitation is controlled by photosynthesis. Although many calcite rich sediments may have largely allergenic source of carbonate, many other lacustrine carbonate sediments are truly androgenic. Their principal constituents have been precipitated directly from the water column15.

The concentrations of carbonate in the sediments, Table 3 and Fig. 9, were 66.2, 68.08, 72.8 and 70.55% at El-Hamama, El-Haniea, Susa and Ras alhilal, respectively. The higher value of carbonate is attributed to the aquatic plants and phytoplankton applied to extract CO2, and thus promote precipitation of carbonate with the increase of pH. A gradual increase in carbonate content from east to west side is recorded. The higher values are probably due to biogenic precipitation of organize by aquatic organisms building their calcareous shells16, and/or due to the calcium rich water where CaCO3 is precipitated with increase of pH during photosynthesis.

Table 3: The concentrations of total organic carbon and the carbonate content of the studied sediment

Ratio Station TOC % CO3%

1 1.6 66.2 2 1.42 68.08 3 2.6 72.8 4 1.15 70.55

Were: 1 El-hamama sites, 2 El-Haniea sites, 3 Susa sites, 4 Ras ahilal sites


1 2 3 40

10

20

30

40

50

60

70

Station

Car

bona

te %

Carbonate%

Station

Car

bona

te %

1.0 1.5 2.0 2.5 3.0 3.5 4.0

66

67

68

69

70

71

72

73 Carbonate %

Fig. 9: The concentrations of (carbonate %) of the studied sediment

The distribution of carbonate is a function of the hydrodynamic regime and the magnitude of physical energy which might affect the degree of breakdown of skeletal materials and their subsequent redistribution17. Generally, the content of carbonate depends on the type of sediments. However, the sediments of investigated area are mainly calcite and magnesium calcite, to explain the high carbonate content15.

Aliphatic hydrocarbons of the sediment samples

Table 4 gives the total concentrations of the n-alkanes ranging from C12 to C40 diagnostic criteria useful for the identification of natural or anthropogenic origins and granulometric parameters for the sediments. The concentrations below their limits of detection were given a value of zero for the calculation. In the present study. The total n-alkanes varied from 26.313 to 1069.183 ng/g (dry weight). Higher concentrations occurred at sites susa port. Lower concentrations were found for samples from sites EL-hamama and Ras alhilal and EL-haniea, Figs. 10-12 show the individual concentrations of aliphatic hydrocarbons in sediment samples.

Table 4: The concentrations (ng/g) of aliphatic hydrocarbons of sediment samples

Concentration ng/g Station name

1 2 3 4 Average

C12 ― ― 80.996 3.622 42.309 C13 2.790 ― 21.060 11.925

Cont…

Int. J. Chem. Sci.: 11(2), 2013 845

Concentration ng/g Station name

1 2 3 4 Average

C14 14.900 3.990 8.189 1.140 7.055 C15 0.000 ― 16.580 ― 8.290 C16 46.940 ― 3.802 ― 25.371 C17 31.799 ― 159.700 ― 95.750

Pristane 22.300 13.230 81.840 15.260 33.158 C18 6.446 1.965 10.010 1.367 4.947

Phytane 6.647 5.224 40.040 3.088 13.750 C19 7.734 1.100 97.470 1.701 27.001 C20 27.310 1.865 26.830 18.150 18.539 C21 5.323 1.854 28.810 9.605 11.398 C22 18.450 3.537 36.300 5.120 15.852 C23 13.750 5.409 103.630 5.406 32.049 C24 33.710 1.680 20.036 1.233 14.165 C40 163.988 4.912 455.770 ― 208.223

∑ALIP 402.087 44.767 1191.063 65.692 425.902 ∑n-alkanes 373.14 26.313 1069.183 47.344 378.995

Sample


Indi

vidu

al c

onc.

(g/

L)

μ

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13

160140120100806040200



Indi

vidu

a l c

onc.

(ng /

L)

C40C24

C23C22

C21C20

C19Ph

ytane

C18Pris

tane

C17C16

C15C14

14

12

10

8

6

4

2

0


Fig. 10: The individual concentrations (ng/g) of aliphatic hydrocarbons for sediment samples (1 and 2)



Indi

vidu

al c

onc.

(ng/

L)

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13C12

400

300

200

100

0



Indi

vidu

al c

onc.

(ng/

L)

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13C12

181614121086420


Fig. 11: The individual concentrations (ng/g) of aliphatic hydrocarbons for sediment samples (3 and 4)

ALIP (Sample 1)ALIP (Sample 2)ALIP (Sample 3)ALIP (Sample 4)

Sample 4

Sample 3

Sample 2

Sample 1


Indi

vidu

al c

onc.

(ng/

L)

C40C24

C23C22

C21C20

C19Phy

tane

C18Pris

tane

C17C16

C15C14

C13C12

400

300

200

100

0

Fig. 12: The individual concentrations (ng/g) of aliphatic hydrocarbons for

sediment samples from (1 to 4)

The average total n-alkanes concentrations was 378.995 ng/g (dry weight) (Table 4). The concentration of TALIP in sediments (Table 4) varied from 44.767 to 1191.063 ng/g with an average of 425.902 ng/g (dry wt.), This value was less than the recorded level for clean urban sites in Scotland, UK; with an average value of 3003 ng/g (wet weight)18. However it is less than the recorded level for Black sea, which was ranged

Int. J. Chem. Sci.: 11(2), 2013 847

from 1200 to 24000 ng/g of sediment19. The high concentrations was recorded at site (Susa region) (Fig. 13).

1 2 3 40

200

400

600

800

1000

1200

Station

TALIP (ng/g)

TAL

IP (n

g/g)

Fig. 13: The relationship between the TALIP concentrations (ng/g) for

sediment samples and stations

It was stated that, Pr and Ph are products of geological alteration of phytol and other isoprenoidyl natural products, and are not primary constituents of most terrestrial biota8. Pr and Ph are presented in most petroleum oils in a ratio of Pr/Ph < 1, so the detection of these two components is often used as good indicators of petroleum contamination. However, a high concentration of pristane alone can be derived from zooplankton20. In uncontaminated sediments, the ratio Pr/Ph is > 1. Typically between 3 and 510.

Table 5 showed that Pr/Ph was > 1 for all stations reflecting biogenic origin. The present study showed that all stations recorded CPI < 1 which may reflect microbial activity. The ratio of (n-C17/pr) in sites (El-Hamama, susa port) was > 1 that reflecting to biogenic origins and the ratio of (n-C18/ph) in all sites was < 1 that reflecting to petrogenic sources (Table 5).

Table 5: Total aliphatic hydrocarbons (ng/g) and some diagnostic ratios of sediment samples

Ratio station

TALIP (µg/L)

Total n-alkanes (µg/L) (C17/pr) (C18/ph) CPI Pr/Ph

1 204.087 373.14 1.4259 0.9697 0.19 3.3554 2 44.767 26.313 Zero 0.3761 0.46 2.5325 3 1191.063 1069.183 1.9513 0.25 0.66 2.0439 4 66.692 47.344 Zero 0.4426 0.54 4.9417


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1. UNEP/ECE/UNIDO/FAO/UNESCO/WHO/IAEA, Pollutants from Land Based Sources in the Mediterranean Sea, UNEP Regional Seas Reports and Studies No. 32, UNEP, Geneva (1984).

2. K. A. Burns and A. Saliot, Petroleum Hydrocarbons in Mediterranean Sea a Mass Balance, Marine Chemistry, 20, 41-157 (1986).

3. R. B. Clark, Marine Pollution. Fourth Edition, Oxford: Claredon Press (1997) pp. 270.

4. J. K. Volkman, D. G. Holdsworth, G. P. Neil and Jr. H. J. Bavor, Identification of Natural, Anthropogenic and Petroleum Hydrocarbons in Aquatic Sediment Science of the Total Environmental, 112, 203-219 (1992).

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Revised : 13.03.2013 Accepted : 16.03.2013

a study of aliphatic hydrocarbons levels of … · (31.421 µg/l). the maximum concentration at...

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